Williams, Todd Andrew (2016-12). The Effect of DC Voltage on Fibrous Debris Bypass Through a Containment Sump Strainer. Master's Thesis.
Public safety has long been one of the chief design concerns for Nuclear Power Plants
(NPPs). For this reason, the design of a NPP must include plans for different accident scenarios called Design Basis Accidents (DBAs). One such DBA is called a Loss of Coolant Accident (LOCA); Pressurized Water Reactors (PWRs) are particularly prone to them.
In order to better understand the phenomena associated with a LOCA, a great deal of research has been undertaken. In particular, many studies have been done under the designation Generic Safety Issue-191 (GSI-191). GSI-191 seeks to better understand the secondary effects of a LOCA such as the pressure drop and debris bypass of the containment sump strainer and the impact that both can have on the Emergency Core Cooling System (ECCS).
The present study was undertaken to build upon previous work that sought to determine whether or not a voltage applied to the sump strainer would affect the amount of fibrous debris bypass. To this end, a vertical strainer made from a perforated steel plate was installed in a horizontal flow loop. A filter bag was installed downstream from the strainer to collect the debris bypass. The fibrous debris was made from one-side baked NUKON fiberglass insulation. Measurements were also taken of the pressure drop across the debris beds. A total of 19 tests were carried out across five different voltages.
No significant difference was observed in either the bypass or the pressure drop between the different voltages. The test results may have been affected by the fact that the present study involved water that was cooler than previous studies. The results may have also been affected by leaks in the test section. Furthermore, the use of multiple NUKON mats may also have affected the results. A study on the sensitivity of the debris bypass to kinematic viscosity could help shed some light on the former problem.